Re: Cat's eyes

[John Denker <jsd@MONMOUTH.COM>]

At 10:03 AM 9/6/00 -0400, Ludwik Kowalski wrote:
> The size of the spot was more or less
> the same as the size of the iris.

Not surprising.  I assume you mean "pupil" not "iris".

> The glowing eyes of the cat were as large as the entire
> exposed parts of eyeballs.

Not surprising.  Implies experiment was done when the cat was dark-adapted.

> Do cats have irises ?

Sure.

For a moderately light-adapted cat, see e.g.
  http://www.andrew.cmu.edu/user/mckinney/closeupCat.jpg

Almost everything you see is either pupil or movable iris -- as opposed to
immovable sclera.  When fully dark adapted, all the green (iris) will be
retracted.  A fully dark-adapted cat has a huge numerical aperture.

When fully daylight-adapted, the pupil becomes 4 or 5 times narrower than
shown in that picture.

> Clarence Bennett wrote:
>  Does anyone know whether cats have a full range of accomodation?

Sure they do.  They'd have a hard time stalking and catching prey if they
didn't.